<!DOCTYPE html>
<!-- 改变所有的标题元素的背景色为 # bbffaa -->
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript" src="jquery.min.js"></script>
<script type="text/javascript">
	$(document).ready(function() {
		 $("h1:header").css("background-color","#bbffaa");
	});
</script>
</head>
<body> 
	<h1>22</h1>
	<h1>22</h1>
	<h1>22</h1>
	<h1>22</h1>
	<h1>22</h1>
	<div>2</div>
</body>
</html>